1. Field of the Invention
The present invention relates to a motor with power-generating coil module and, more particularly, to a motor having a simple structure.
2. Description of the Related Art
Referring to FIG. 1, an invention of a Taiwan patent with patent number M290267 and entitled as “Light Emit-able Cooling Fan” is shown and regards to a conventional cooling fan capable of power generation, wherein the cooling fan includes a base 81, a fan wheel 82, a driving unit 83, a power-generating unit 84 and a light emitting unit 85. The base 81 has a shaft tube 811. The fan wheel 82 is rotatably coupled with the shaft tube 811 and has a carrier 821, with an end edge of the carrier 821 extending towards the base 81 to form an annular wall 822. The driving unit 83 includes a first magnet ring 831 and a first coil member 832, wherein the first magnet ring 831 is mounted on an inner surface of the annular wall 822 of the fan wheel 82, the first coil member 832 surrounds the shaft tube 811, and there is a first radial gap “A1” between the first magnet ring 831 and the first coil member 832. The power-generating unit 84 includes a second magnet ring 841 and a second coil member 842, wherein the second magnet ring 841 is mounted on an end of the first coil member 832, adjacent to the carrier 821. The second coil member 842 is mounted on the fan wheel 82 and also adjacent to the carrier 821, and there is a second radial gap “A2” between the second magnet ring 841 and the second coil member 842. The light emitting unit 85 is arranged adjacent to the carrier 821, electrically connects with the second coil member 842 and has a LED bulb 851 mounted through the annular wall 822 of the fan wheel 82.
When the cooling fan runs, the first coil member 832 is electrically energized to generate an alternating magnetic field so as to move the first magnet ring 831, and thus the fan wheel 82 turns. At the same time, the second coil member 842 is moved relatively to the second magnet ring 841 by the rotation of the fan wheel 82, and thus the second coil member 842 generates an induced current by the magnetic field of the second magnet ring 841 due to flux linkage. Finally, the LED bulb 851 of the light emitting unit 85 operates to emit light by the induced current.
In order to provide a desirable driving performance of the driving unit 83, a surface of the first magnet ring 831 and a surface of the first coil member 832 facing each other across the first radial gap “A1” should have large areas, so as to improve the magnetic force between the first magnet ring 831 and the first coil member 832. Similarly, in order to improve the electric power generation of the power-generating unit 84, a surface of the second magnet ring 841 and a surface of the second coil member 842 facing each other across the second radial gap “A2” may also have large areas. However, referring to FIG. 1, it is apparent that an increased axial size of this cooling fan is thus caused by the above said large areas of these surfaces. Furthermore, the structure of this conventional cooling fan is complex since the first magnet ring 831 and the second magnet ring 841 are both made of magnet but separately arranged on the fan wheel 82 and the base 81.
Referring to FIG. 2, another invention of a Taiwan patent with patent number I343518 and entitled as “Light Emit-able Cooling Fan” is shown. In comparison with the previous cooling fan, this cooling fan has a fan wheel 91 coupling with a first magnet ring 921 of a driving unit 92 by an inner surface of a lateral wall 911 of the fan wheel 91, and the first magnet ring 921 can be driven by and moved relatively to a first coil member 922 of the driving unit 92. Besides, a bottom edge of the lateral wall 911 of the fan wheel 91 further connects with a second coil member 931 of a power-generating unit 93, with the second coil member 931 capable of moving relatively to a second magnet ring 932. Furthermore, a light emitting unit 94 is mounted on the fan wheel 91 and electrically connects with the second coil member 931. Accordingly, when the first coil member 922 is electrically energized to turn the first magnet ring 921 as well as the fan wheel 91, the second coil member 931 moving relatively to the second magnet ring 932 can generate an induced current to operate the light emitting unit 94.
However, owing to the trend of microminiaturization and thinning tendency of motors, it is desirable to reduce the length, width and thickness of every elements of a motor, including the fan wheel 91, and thus an area of the bottom edge of the lateral wall 911 is quite limited. Therefore, it is difficult to dispose the second coil member 931 on the bottom edge of the lateral wall 911 and may lead to a high manufacture cost since the second coil member 931 has a complex winding structure as shown and can only be arranged in such a limited area of the bottom edge of the lateral wall 911. Moreover, due to the limited area of the bottom edge of the lateral wall 911, even though the second coil member 931 can be mounted on the bottom edge of the lateral wall 911, the second coil member 931 can only provide a small power in electrical generation.
As a result, an improved motor is needed to have a small size and a simple structure and to generate larger electrical power.